Bumgarner or Sale: Who's the Best Young Southpaw after Kersh?

No one will argue that Clayton Kershaw isn't the best pitcher in Major League Baseball at 25 years old or under, and I doubt many will refute the idea that he's well on his way to being the best pitcher of my generation. Heck, he just signed a seven-year, $215 million deal with the Dodgers -- giving him the largest average annual salary for a player in baseball history -- and has led all qualified starters in ERA in each of the past three seasons. Based on these facts alone, we can conclude that Kershaw takes the cake when it comes to dominant pitchers (both young and old).

But who's the next-best 25-or-under southpaw in baseball right now? This is a difficult question to answer, if only because there aren't many elite lefties. While Matt Harvey, Stephen Strasburg, and Jose Fernandez are the obvious leaders of an insanely talented crop of young right-handed pitchers, the same cannot be said for young southpaws outside of Kershaw. Two names stand out above the rest, however, and that's Chris Sale and Madison Bumgarner.

Both are 24 years old. Both are entering their fifth full season in the majors. Both own career ERA marks around 3.00 (3.08 for Bumgarner, 2.97 for Sale). Both finished in the top 10 for their respective league's Cy Young Award voting last season. Both are exceptionally towering in stature (Bumgarner is 6'5", 235; Sale 6'6", 180) and both played for teams that didn't make the playoffs in 2013. The similarities are almost uncanny, am I right?

Unnaturally similar resumes aside, though, these two have clearly established themselves as the top 25-or-under southpaws in baseball after Kershaw. Which one is "better", you ask? Let's find out by evaluating the two in these areas: Command, ability to generate strikeouts and batted ball results.

Command/Control

Though Sale and Bumgarner boast similar pitch frequency heat maps over the past two seaons, one holds a distinct advantage in respect to command and control -- an aspect that is crucial to consider when evaluating starting pitchers. You can pump upper-90s fastballs around the plate all day long, but if you can't hit the mit where you need to, you won't last long in the majors.

• Pounding the zone: Since 2012, Sale owns a 52.9% zone rate compared to Bumgarner's 49.9% mark. Yes, throwing more pitches in the zone doesn't always lead to success, but in this case it does: Sale's 37.9% called strike rate (third best among LHP since 2012) trumps Bumgarner's 32.5%.
• Restricting free bases: Given his ability to pound the strike zone and paint the corners at a high rate, a lower walk rate has followed suit. Sale owns a 5.9% walk rate over the past two seasons while Bumgarner retains a slightly higher 6.7% walk rate, which is nearly at the 7.2% league average mark.

Command Advantage: Sale.

Strikeout Ability

If command is the most important means by which to evaluate a starter, then strikeout capacity and ability is an easy second, at least for me. Fortuitously, this is an area in which both Sale and Bumgarner have excelled to this point in their respective careers.

But the way in which the two go about punching out opponents is different; a whopping 49.8% of Sale's strikeouts occur in the strikezone (third-highest among qualified lefties since 2012) while Bumgarner uses his deception to expand opponents zones, as 59.4% of his strikeouts transpire outside the zone.

• Expanding the zone: Since 2012, Sale owns a 30.4% chase rate juxtaposed to Bumgarner's 29.1%, so Sale gets the slight nod here. Neither are dominant in this area, though, as the league average mark in the last two seasons is 28.5%. We should consider that opponents swing more frequently at Bumgarner's stuff (47.7%) than Sale's (45.4%), however.
• Swing and a miss: Sale separates himself from Bumgarner a bit more in generating swings-and-misses, however, as he owns a 25.2% miss rate opposed to Bumgarner's 23.6% miss rate. Neither are exceptional in this respect, again, as the league mark is 21.2% and league lead is owned by Francisco Liriano at 30.7%. The two are nearly identical when it comes to swinging strikes, with Sale boasting an 11.5% swinging strike rate and Bumgarner an 11.2% rate.
• Simple Strikeouts: Then there's the generic strikeout rate. Sale reigns supreme here again, holding true to a 25.5% strikeout rate (sixth-best since 2012) compared to Bumgarner's 23.6%.

Strikeout ability advantage: Sale.

Batted Ball Results

Though I'm not the biggest proponent of evaluating pitchers strictly off opponents' numbers against them, they do maintain at least some merit. Looking at how batters fare against a pitcher statistically (i.e. SLG% against) can sometimes shed light on how effective (or uneffective) a pitcher's stuff is from a broad perspective.

• Limiting XBH: While Sale maintains an advantage in command and strikeouts, Bumgarner gets the nod for holding opponents to lower success rates. Over the last two seasons, he's held batters to a .348 SLG% (ninth lowest among qualified starters) while Sale is just percentage points behind at .362 compared to the .402 league average.
• More grounders: The ability to generate ground balls is an elite (and frankly unteachable) attribute for any pitcher, and Bumgarner again outperforms Sale in this regard. With a 47.5% ground ball rate since 2012, he outmatches the 44.7% league mark and trumps Sale, as well, whose 45% ground ball rate is essentially average.
• In play or no? When it comes right down to it, pitchers are considered effective when they limit the amount of pitches that opponents put in play -- less pitches put in play generally leads to less hits. It's really that simple. For Bumgarner, this is another edge over Sale, as he owns a 36.9% in-play rate (fifth-best among lefty starters last season) compared to Sale's 38.8% mark.

Batted ball results advantage: Bumgarner.

So, Who's (Second) Best?

Considering everything we've just discussed, it seems as though Sale is the "better" pitcher, holding advantages in command and strikeouts. However, this is more of a question of preference; do you want a pitcher whose command is slightly better and who strikes out more batters (Sale), or do more ground balls and fewer pitches placed in-play tickle your fancy?

I'll take Sale, but we all know Kershaw is the most elite arm in the game.